Packet-switched voice communications are rapidly displacing conventional circuit-switched voice communications as the preferred mode of communicating in real time between individuals. As a result, various telecommunications protocols, such as the Session Initiation Protocol or SIP and H.323, have been developed to provide computer telephony applications with the features normally present in circuit-switched telephony, such as call forwarding, callee and caller number delivery, personal mobility, terminal-type negotiation and selection, terminal capability negotiation, caller and callee authentication, blind and supervised call transfer, and conferencing.
To converge circuit-switched and packet-switched communications into a single architecture, many manufacturers are using standalone server architectures, also called decomposed server architectures. An example of a decomposed server architecture in an enterprise network is presented in FIG. 1. The architecture 100 includes the enterprise network 102, home proxy servers 104 and 108 in communication with corresponding packet switched communication devices 112 and 116, respectively, and communication managers 120 and 124 serving the communication devices 112 and 116, respectively. An edge proxy server 136 interfaces the enterprise network with an external data network (not shown), such as the Internet. As will be appreciated, the proxy servers effect call directing and session management, redirect functions, directing to media gateways, and user authentication, maintain a map of what IP address a given user has at a selected time, and maintain user profiles and provide subscriber registration; and the communication manager provides, inter alia, call origination and termination services. Each communication device has an extension administered on its corresponding communication manager and a user administered on its corresponding home proxy server.
The decomposed server architecture 100 can fail to provide call origination services in many applications. By way of example, if the communication device 112 makes a call to the communication device 116 using a SIP INVITE message, the message is received by the home proxy server 104 and is forwarded to the edge proxy server 136 and then to the home proxy server 108 of the called communication device 116 due to the use of destination directing. The communication manager 120 of the calling communication device 112 and the communication manager 124 of the called communication device 116 do not receive the INVITE message and therefore are unaware that the call has been made/received. Thus, call origination features will not be activated; that is, call appearances and bridged call appearances will not be illuminated, and class of service and class of restrictions will not be applied. The same problem exists when the communication device 112 calls a device outside of the domain of the home proxy server 104, when digit-dialed calls are directed to a communication manager user within the enterprise network domain but not within the domain of the same communication manager, and communication devices with a contact on a communication manager other than the originator's communication manager.